Coulomb's Law & Electrons

Two spherical objects are separated by a distance of 1.98 x 10-3 m. The objects are initially electrically neutral and are very small compared to the distance between them. Each object acquires the same negative charge due to the addition of electrons. As a result, each object experiences an electrostatic force that has a magnitude of 4.19 x 10-21 N. How many electrons did it take to produce the charge on one of the objects?

2. Relevant equations

F = k q1q2/r^2

N= Q/e

k = 8.99E9 nm^2/c^2
e= -1.602E-19C

3. The attempt at a solution

I used coulomb's law and plugged in the Force as 4.19E-21N, boltsmans constant for k and 1.98E-3m as the r^2.